In a rare admission, the FBI said that it has been looking into Russian meddling in the U.S. election since last summer.

FBI Director James Comey confirmed Monday that the bureau has since July been examining the Russian campaign to meddle in the 2016 American election, and that the federal probe includes an investigation of any coordination between the Trump campaign and the Kremlin effort.

“The FBI as part of our counterintelligence mission is investigating the Russian government’s efforts to interfere in the 2016 presidential election, and that includes investigating the nature of any links between individuals associated with the Trump campaign and the Russian government, and whether there was any coordination between the campaign and Russia’s efforts,” Comey told the House Intelligence Committee.

Comey’s confirmation of the ongoing investigation was an extraordinary acknowledgement.

Speculation about an FBI investigation has roiled Washington and cast a cloud over President Donald Trump’s first months in office.

Democrats on the committee, led by ranking member Rep. Adam Schiff (D-Calif.), sought to tease out what the FBI and the NSA know about any possible ties between Trump advisers and the Kremlin, but in a public hearing Comey could say little about the ongoing investigation. Comey did, however, say Putin was pulling for a Trump victory, given his known dislike for his opponent. If Putin wanted Clinton to lose, Comey explained to Rep. Mike Conaway (R-Tex.), that means he wanted Trump to win.

Democratic members of the committee — in particular, Schiff and Rep. Terri Sewell (D-Ala.) — also asked Comey and Rogers about the activity of former director of National Security Advisor Michael Flynn, who discussed sanctions with the Russian ambassador as a private citizen and did not disclose he was working as a “foreign agent,” lobbying for a firm linked to the Turkish government, while also advising the Trump campaign. While Comey and Rogers largely declined to answer their questions on the matter, that the questions were asked at all perhaps signals that Democratic attention is turning toward investigating Flynn.

Some Democratic members focused their questions on Paul Manafort, the former Trump campaign chief currently sought for questioning in Ukraine in connection with a corruption case there. Rep. Joaquin Castro (D-Tex.) described him as having “a major part of the Trump campaign,” shortly after press secretary Sean Spicer said Manafort had “a very limited role” in the campaign (Manafort resigned after allegations emerged accusing him of receiving payments from Ukraine.) In a statement released after the hearing, Manafort said, “I had no role or involvement in the cyberattack on the DNC or the subsequent release of information gained from the attack, and I have never spoken with any Russian Government officials or anyone who claimed to have been involved in the attack … I am disappointed that anyone would give credence to allegations made by individuals with clear political motives in a blatant attempt to discredit me and the legitimacy of the election of president Trump.”

Rep. Denny Heck (D-Wash.) insisted the investigation “is not about party, it’s about country.” But most Republicans on the panel sought to push the inquiry in a different direction, ignoring the revelation that the president’s campaign is under investigation and focusing instead on the leaks of classified information about contacts between Trump administration officials and Russia.

Trump has railed against the congressional investigation as an attempt to undermine his legitimacy, and on Monday took to Twitter to attack the probe. Trump called the notion that he had colluded with Russia “FAKE NEWS” and said allegations about his connections to Russia had been concocted by Democrats “as an excuse for running a terrible campaign.” (He also tweeted Monday morning, “What about all of the contact with the Clinton campaign and the Russians?,” and, indeed, Nunes asked Comey whether the FBI might look into ties between Russia and the Clinton campaign if pertinent information emerged.)

“The real story that Congress, the FBI and all others should be looking into is the leaking of Classified information,” Trump wrote. “Must find leaker now!”

After the hearing began, Trump tweeted out, “The NSA and FBI tell Congress that Russia did not influence electoral process. Later in the hearing, when asked whether Trump’s tweet was accurate, Comey clarified that communicating such sentiment was “not our intention,” as that was not part of the scope of their investigation.

At a White House briefing the same day, Spicer stressed that this hearing is the first of several, and that “it’s clear nothing has changed” with respect to potential Russian collusion. What is new, he said, is that “Director Comey said certain Obama officials had access to information,” implying that Obama administration officials might have leaked confidential information, such as Flynn’s intercepted communications.

Republican representatives took up the president’s line of attack, with Rep. Thomas Rooney (R-Fla.) and Rep Trey Gowdy (R-S.C.) focusing their questioning on leaks of classified information. (Gowdy himself appears to have accidentally released the name of a CIA source in 2015 in connection with the Benghazi Committee.)

In a round of questions with NSA Director Michael Rogers, Rooney argued that such leaks harm national security and may threaten the reauthorization of Section 702 of the Foreign Intelligence Surveillance Act, a key statute authorizing overseas signals intercept. Rooney contended such leaks harm trust in the legal process to obtain a warrant for foreign intelligence surveillance.

Trump has levelled explosive allegations against his predecessor, claiming on Twitter that President Obama ordered phones at Trump Tower be tapped. “I have no information that supports those tweets,” Comey said, adding the the Department of Justice does not, either. The NSA also said that it has no evidence to support those claims.

After those claims were publicly debunked, the White House suggested that British intelligence may have spied on Trump. Rogers seconded British intelligence’s dismissal of those claims as “nonsense” and “utterly ridiculous,” but added that the intelligence relationship is strong enough to weather the spat.

The FBI probe into Russian meddling reportedly includes three separate investigations being carried out by the Washington, Pittsburgh, and San Francisco field offices. The Washington office is reportedly heading the counterintelligence investigation, which is examining contacts, possible collusion, and financial ties between the Trump team and Russia.

Pittsburgh agents are reportedly attempting to determine who broke into the computer systems at the Democratic National Committee and leaked stolen documents to WikiLeaks.

The San Francisco office agents are investigating the online persona known as Guccifer 2.0, which American intelligence officials have described as a front for Russian intelligence to publish stolen documents.

Rogers noted that the Russians were particularly brazen in meddling in the past presidential election campaign, and he said at several points that they are acting similarly to affect elections in Europe.

“They’ll be back,” Comey said, pointing to upcoming elections in 2018 and 2020.

Update, Mar. 20 2017, 12:16 pm ET: This post was updated to include Comey’s comments on Putin’s presumed preference for Trump and Nunes’s questioning on a hypothetical investigation into potential ties between the Clinton campaign and Russia.

Update, Mar. 20 2017, 12:46 pm ET: This post was updated to include Schiff and Sewell’s questions on Flynn.

Update, Mar. 20 2017, 1:02 pm ET: This post was updated to include Rogers’s comments on the brazenness of Russia’s actions and Comey’s comments that they will be back.